Thoracic surgery frequently involves the surgical creation of a mid-line sternotomy, which is an opening of the chest by some method of cutting through the skin, muscle, cartilage and bone of the central chest and spreading this surgical opening. Commonly this is done to allow additional surgery within the thoracic cavity. Examples of these surgeries include, but are not limited to, coronary artery bypass graft surgery (CABG) and heart valve replacement surgery. Such surgeries may require the patient be supported with cardio-pulmonary bypass. Thoracic surgeries may employ other surgical access techniques besides the mid-line sternotomy. When the surgical opening is closed, sternal wires may be used to do so.
Sternal wires or high-tensile-strength suture material may be employed to affect the closing of a surgical access site due to their high tensile-strength and ability to remain closed or tied. The high strength of such wires helps the surgeon properly approximate the alignment of the tissues (including bone and cartilage) on either side of the sternotomy and maintain this alignment while the sternum heals. Sternal wires may be used with other surgical access sites. For example, such wires may be used in orthopedics to couple or connect other tissues such as bone.
Because many thoracic surgeries are extremely invasive patients often require a significant degree of post-operative monitoring. Such monitoring might include, but is not limited to, monitoring of the patient's electrocardiogram (ECG), body temperature, blood oxygen saturation level, local sounds, and/or electrical impedance between two or more locations. This helps a medical staff minimize the impact to the patient of complications from the surgery should these develop, as well as to generally expedite the patient's recovery from surgery. Such monitoring may continue for an indefinite period of time, including long-term outpatient care. Unfortunately, monitoring modalities external to the patient may be unwillingly disconnected from the patient. Such monitoring is also subject to interference from nearby devices and may have some degree of inaccuracy for values considering the distance from the source.
Also, because thoracic surgeries are extremely invasive, patients may require therapeutic interventions during convalescence such as, for example, temporary cardiac pacing, cardiac defibrillation, and synchronous cardio-version of abnormal cardiac rhythms. Such therapeutic interventions may be emergently needed and potential life-saving (e.g., cardiac defibrillation for ventricular fibrillation). Therapeutic intervention devices external to the patient may be vulnerable to unintended functional disconnection from the patient, may cause pain when current transmits through due to the patient's skin, may be susceptible to mechanical damage, liquid intrusion, and the like, may be more susceptible to infection compared to fully-implantable systems, and may be less energy-efficient and effective than implantable counterparts because the therapeutic current is partially dissipated when passing through the patient's skin and other tissues.